Hitherto, a data communication system using a telephone line includes a home banking system and a pager system which is one of selective calling systems. In the data communication system, the efficiency of using the communication line is improved by limiting an amount of data in one communication operation from a data sender to a pager of a destination of the call (a called pager).
Therefore, a data sender is permitted to transmit, to the pager, only the telephone number, to which a called party should call or reply. Moreover, even if an amount of data which is to be transmitted in one communication operation is large, only time information and information specifying the day and time can be transmitted as well as the telephone number to which the called party should call.
When a numeric message is transmitted from a data sender to the numeric pager, a push phone generally is the most appropriate data transmission device. That is, a data sender operates a ten-key of the public push phone connected to the telephone network to follow an announced operation instruction transmitted from a paging service company to input a message so as to transmit it to the pager.
In a pager system using a push phone as the data transmitting apparatus, conforming RCR STD-43 standard shown in FIG. 31, the data sender operates numeric keys for specifying kana characters and alphabets of two digits, except numerals, in accordance with a free word conversion matrix to input a message formed by the free word data which is to be transmitted to the pager. Therefore, the free word data is transmitted to the pager through the paging service. Thus, a message including kana and alphabets, except numerals, can be displayed.
When the free word data is transmitted, the data sender first operates the push key to input an identification code in the form of two digits dial data as "*2*2"(--:hyphen hyphen) indicating that the following data is free message data, and then inputs free word data. The pager which has received the above data recognizes that received data is the free word data in accordance with the identification code, and then makes a reference to the free word conversion matrix table storing data following the identification code so as to convert the above data into kana characters and alphabets which are then displayed.
However, since display of a message using the free word data on a numeric pager of the conventional pager system has a format of the free word conversion matrix table limited to 10.times.10=100 types, display can be performed only with the 100 combinations of characters (katakana, alphabets, numerals, illustrations, and symbols). What is worse, an amount of data which can be transmitted is defined such that one character is expressed by two digits (8 bits) of numerals. Therefore, a rate of occupying the message data in the transmission data is larger than the fixed form message.
Therefore, when data transmission is performed by using the free word, the data sender encounters a difficulty in transmitting the inputted free word data and additional data including data for displaying the name of the data sender, urgent message data (including notification control as well as display control) and the like in one communication operation.
The paging service includes the following two main services to be adaptable to the type of the message data which is received by the pager.
One of the services is NP paging service in which a pager number (calling number) of the called pager is input by the data sender and a message is input by the push dial. A service center of the paging service which has received message transmits a stream of data composed of a 4-bit pattern corresponding to the dial data. A numerical pager (hereinafter expressed as "NP") receives the stream of data so that a message in the form of a string of numerals corresponding to the dial numbers is displayed.
Another service is IP paging service in which a data sender requests paging, and then announces a message to an operator of the service center. The operator converts the message into the message data composed of 7-bit code data in accordance with a set of alphanumeric characters shown in FIG. 32, and then transmits the message data to the pager. Thus, the alphanumerically pager (hereinafter called "IP") receives data so that the message in the form of characters is displayed.
Although the two paging services are used widely, existence of the two types of paging services results in data transmission of a message formed of simple characters to a pager being impossible to be received and displayed in a case where the pager used by the called party is NP. As a result, the data sender sometimes feels inconvenience.
The alphanumeric character set shown in FIG. 32 is in the form of a code matrix called ISO 646-1983E conforming to International Organization for Standardization (ISO) which enables control characters from "00" (HEX) to "0F" (HEX) or those from "10" (HEX) to "1F" (HEX) to be adapted to character types of various nations and thus to be extended. Thus, the set is used widely.
However, if the character set is intended to be adapted to the NP paging service, it cannot satisfactorily be adapted to dial data. The NP cannot receive the message data conforming to the alphanumeric set and display a character message.
An object of the present invention is to provide a data receiver apparatus in which control information for instructing display of a name of a data sender, an urgent call, and the like are simultaneously received with a message based on the received free word data so that the forms of display and notification of the free word message are controlled on the basis of control information.
Another object of the present invention is to provide a data receiver apparatus which can be adapted to the dial data and which is capable of displaying a message in the form of an alphanumeric set.